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Is my rear main leaking or no ?

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Candymancan View Drop Down
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    Posted: Mar/25/2023 at 8:29pm
So ive done this twice now.. rear main seal leaks a qusrt every 400-500 miles.. both times i did the rear main..  it litterally didnt slow the oil leak down much at all.  The last time it did a little but not by much.

Oil pan is dry..  intake on top is wet from crusty old oil and a coolant leak on the bolt but thats it.  When i pulled the inspection plate off.  Its dry behind.. but the plate up front is wet.  Its wet from the top little 2 inch lip that slides inside up against the bearing cap all the way down in a stream. 

But the crank where the flexplate meets itself is dry bellhousing imside isnt soaked either..  Is it still the rear main but that inspection plate lip that slides inside is blocking it ?  Snd it runs down outside..   or is this leak from the oil pan perhaps ?  But if its the pan wouldnt it be wet where the pan meets the cap.  It doesnt seem like it is but i dunno.

Im getting tired if taking this apart.. lushing out seals.. pushing in seals.  I sware i almost feel like taking a socket extention on the oil pan lip and smacking it with a hammer to smash the oil pan on the lip tighter.


But i dunno.. is it the rear main ??  

Is it was.. wouldnt the crank/flexolate connection be wet with oil... why is the inspection plate lip l/front wet instead.  And no it isnt the valve covers either.. i redid those and my camera shows it dry




Edited by Candymancan - Mar/25/2023 at 8:35pm
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Candymancan View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Candymancan Quote  Post ReplyReply Direct Link To This Post Posted: Mar/25/2023 at 9:09pm
Also sitting idle with the inspection cover off.. laying under the keep for 1 hour... 1 hour...... i saw not a drop of oil... maybe its leaking at higher rpm when driving ??? Why ?

I have a 90 Grand wagoneer btw amc 360
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ITSWHAT Quote  Post ReplyReply Direct Link To This Post Posted: Mar/25/2023 at 9:17pm
might be the plug for the cam in the back of the block.  If it leaked it would appear to look as it was the rear main.

1968 AMX 390 5speed - Alfano IFS
1969 AMX tube chassis - FARMX
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Post Options Post Options   Thanks (1) Thanks(1)   Quote bikerfox Quote  Post ReplyReply Direct Link To This Post Posted: Mar/25/2023 at 10:08pm
feel 4 ya, guy.  i had a similar issue with the 401.  long story short:  if you are attempting
to replace the rms with the engine in the vehicle you run the risk of not doing it correctly.
at the very least, we installed the intake with rtv in the rear and then dev'd a rear intake
leak.  only when we removed the engine were we able to fix the problem, as it was easier
to do the prep and the install w/the engine removed.  since you've done it twice, i would
HIGHLY recommend, if possible, to get a more experienced buddy to help you the third
time around.  i think it always helps to have another set of eyes on the process.
1969 Rebel SST (1970-1987)
1968 AMX (2005-2011)
1969 SC/Rambler (2011-2019)
1970 Javelin (2019 to ?)"Jane"
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Candymancan View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Candymancan Quote  Post ReplyReply Direct Link To This Post Posted: Mar/25/2023 at 10:10pm
I was thinking that too.  But im not sure..  my bore scope is a tad too thick to get up in there ti see.

Anyway..i revved the engine for 15 min at 2500 rpm and then shut it iff and boom leak.. but the rear main where the crank/flexplate is again dry as a bone.

The leak came from the plate where the starter is bolted too..  I stuck my bore scope in there.  No oil.  But where that plate meets is the oil pan lip.  Its wet there.  So F IT..  i took a hammer and long screw driver with a flat tip not pointed tip so i dont pike the oil pan.  And i bashed the crap out if the lip on the pan where it meets the bearing cap.

Wiped it all down.. ran the engine for 10 min. And revved it to 2000-3000 rpm and shut it off.. and its dry now ?   But im testing it again idling it lingee and then ima rev it for 5-10 min like i did before.

Maybe its the stupid oil pan leaking ??  First time.  I di specifically remember it leaking worse after i did the rear main.. 2nd time (recently)  it slowed it down but still leaks badly..   I wonder if this oil pan isnt sealing right on the lip there.   First time i used the cork/rubber gasket set.

This 2nd time around i blobbed a thick layer of rtv there. And around the entire pan.  No cork.  I wonder if the rtv needed to be thicker and thats why it could ( could) be leaking from the pan ?  But why would it leak with the rubber as well...

Well see after this last idle/rev test.  If it still leaks.. i dunno what to do then..  the rear main is dry the crank is dry the flex plate is dry.. so it couldnt possibly be the rear main could it ???

I wish my bore scope could fit in there to check that cam shaft nut...   maybe if i remove the starter i can get the scope up in there from there.

I dunno... crossing my fingers.. i hope me bashing the oil pan lip did it..

Yea i know i dented my pan... but i dont care.  Ive done this to a leaking 4.0 gasket up front and it stopped the leak.  400k miles now on that engine..


Edit: also again the crank/flex plate is dry..  litterally no oil at all where thr bearing cap U is on the crank.. So im perplexed if its this rear main


Edited by Candymancan - Mar/25/2023 at 10:15pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bikerfox Quote  Post ReplyReply Direct Link To This Post Posted: Mar/25/2023 at 10:14pm
Originally posted by Candymancan Candymancan wrote:

Also sitting idle with the inspection cover off.. laying under the keep for 1 hour... 1 hour...... i saw not a drop of oil... maybe its leaking at higher rpm when driving ??? Why ?

I have a 90 Grand wagoneer btw amc 360

lots of leaks don't manifest when the engine is sitting or at idle. it takes pressure to make
that leak happen in many cases.  one product i used a while ago to determine where the
i would suggest cleaning all suspected areas of leakage, pour in the product, go for a drive,

another pressure leak can sometimes come from a mal-tightened valve cover.  are your valve cover bolts correctly tightened? are your valve cover gaskets fairly fresh?
1969 Rebel SST (1970-1987)
1968 AMX (2005-2011)
1969 SC/Rambler (2011-2019)
1970 Javelin (2019 to ?)"Jane"
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Candymancan Quote  Post ReplyReply Direct Link To This Post Posted: Mar/25/2023 at 10:50pm
Welp still leaks.. oddly after i rev the engine and turn it off.. is when it starts to pour out...  lol... uhg i give up on this pos amc engine.

Just gonna keep refilling it with cheap rump wal mart oil i guess... Im not doing this rear main a 3rd time when i habe other things to fix i wanna bash my head on the wall
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bikerfox Quote  Post ReplyReply Direct Link To This Post Posted: Mar/25/2023 at 10:50pm
Originally posted by Candymancan Candymancan wrote:

The leak came from the plate where the starter is bolted too..  I stuck my bore scope in there.  No oil.  But where that plate meets is the oil pan lip.  Its wet there.  So F IT..  i took a hammer and long screw driver with a flat tip not pointed tip so i dont pike the oil pan.  And i bashed the crap out if the lip on the pan where it meets the bearing cap.

IMO, you are shortcutting and bashing engine parts isn't the way to go.  the oil pan needs to be dropped.

This 2nd time around i blobbed a thick layer of rtv there. And around the entire pan.  No cork.  I wonder if the rtv needed to be thicker and thats why it could ( could) be leaking from the pan ?  But why would it leak with the rubber as well...

Nooooooo, NO rtv on the oil pan. it isn't needed and creates more problems than it solves.  the pan needs to be dropped and the pan rails need to be checked to see if they're "flat."  i bet some of the pan holes are high and some are low.  this needs to be fixed.

Well see after this last idle/rev test.  If it still leaks.. i dunno what to do then..  the rear main is dry the crank is dry the flex plate is dry.. so it couldnt possibly be the rear main could it ???

as i already mentioned get some of that dye and a led dye locater and see if the rms is the issue.

I wish my bore scope could fit in there to check that cam shaft nut...   maybe if i remove the starter i can get the scope up in there from there.

i like that idea!
1969 Rebel SST (1970-1987)
1968 AMX (2005-2011)
1969 SC/Rambler (2011-2019)
1970 Javelin (2019 to ?)"Jane"
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Candymancan Quote  Post ReplyReply Direct Link To This Post Posted: Mar/25/2023 at 11:38pm
Well bore scope further in i see a line of oil the flex plate is throwing in thr bell housing.. thays why its dripping by the starter plate on the bellhousing...  whats weird is its throwing the oil on the convertor side if the flexplate

Question my pcv valve seems fine it rattles and is clean i put a tube long enough on the intake and breathed in and out.. no clogs there behind the carb

But i removed the factory air hat and put a edlebrock hat and cap on the fill tube.  I sware i remember like 5 years ago when i did that the oil loss got worse.

Could there be too much pressure in the engine?  I heard thr pcv doesnt work with high rpms.  So if my oil fill cap has no air hat to suck air out of it could there be a build up of pressure inside the engine.   ?  

I did rtv this 2nd time around becsuse i wanted to be sire it wasnt a oil pan leak from cork.  Well it clearly isnt that.   The pics i took inside the bellhousing of the flexopate showing a line of oil going up the entire bellhousing inside.  So its flinging oil.  Nothing wrong with rtv on the oil pan besides it being hard to get off .. Clearly it isnt leaking from the pan now that i looked deeper inside.. 

What problems does it cause exactly if done right.  ?  Wheb i first did my rear main 6 years ago the cork was hard as a rock and 70% of the pickup tube was blocked by cork.  So cork can also do what people say rtv does.  Also i made sure it was flat.. ive been working on cars for 20 years im not fully dumb at this lol..  this isnt the first rear main ive done either.. but this amc 360 is a royal pita.. the 360 magnum and 4.0 and 318s ive done never had this issue


Also fyi cork leaks with synthetic oil.  And there is no other gasket but cork with these amc engines.
 
Ill try the seal a 3rd time.. ( ill use SCE not fel pro) i heared SCE is better.  Before i do this do you think adding another breather to the valve covers.  Or a breather line from the oil tube to the air hat.  Would possibly help with any possible pressure im seeing in the engine ?  

 Im almost curious to try this... Cut a hole in the top of the edlebrock air hat and thread a 90 degree angle barbed fitted on it and put a tubed cap back on the oil filler neck.  Or something like this.  Im seriously wondering if this is the issue.   Every engine has this.  And i removed it by just putting a cap on it but no vacuum line



Edited by Candymancan - Mar/26/2023 at 12:01am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Candymancan Quote  Post ReplyReply Direct Link To This Post Posted: Mar/26/2023 at 12:41am
Haha.. i jist found an old thread from back in 2017.. where i asked why is my rear main leaking after i removed the factlry air hat and the breather tube from the oil filler neck.

In the thread i said that the leak stopped wheb i put the factory air hat back on..

Bht thats 6 years ago i cant remember if that actually stopped it or not.  Clearly i put the aftermarket eldbrock back on for some reaso ..

Sooo could no vacuum line to the intake hat on the oil filler neck cap be causing the engine to have too much crankcase pressure at high rpm ??
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